1. Field of the Invention
This invention relates to an overwrapping film using a plastic base film and a method of producing the same.
2. Description of the Prior Art
Tape cassettes commercially available for use in cassette tape recorders or the like are sold at stores and are typically packed with an overwrapping film which employs a plastic base film. In order to ensure easy visual distinction from other merchandise, the overwrapping film generally has a printed display region to show a trade name and other data which, for example, could represent the audio characteristics of the particular cassette. The overwrapping film for articles exhibited and sold in stores should be finished and in a satisfactory condition for enhancing the image of the merchandise contained therein since the appearance thereof usually exerts a great influence on the buyer. Typical materials adapted to produce overwrapping films for tape cassettes include transparent synthetic resins or plastics such as polypropylene.
A display region is formed on each film by printing with a variety of paints so as to attain a favorable esthetic effect to the overall design. Furthermore, by utilizing the thermal contraction property of the plastic material, a tightly-packed configuration is obtained with the contraction of the overwrapping film subsequent to packing.
In attaining an adequate fit of the overwrapping film through such a thermal contraction treatment, there also exists the possibility of deformation of the printed display region occurring on the overwrapping film during, and as a result of, the thermal contraction treatment. Particularly, when a finished appearance is to be achieved by furnishing a metallic gloss to the printed display region, the harmful effects derived from such thermal contraction can be considerable. According to a solution taught by the prior art, hot stamping is executed for setting a metallic gloss to a cassette-tape overwrapping film. However, some problems inherent in this method include deviation of the stamping position due to a post-treatment, restriction on the stamping area, deterioration of the gloss resulting from finishing thermal contraction, difficulties in producing a continuous supply of products with satisfactory overwrapping, and an increase in the production cost.